Photography-specific digital camera apparatus and methods useful in conjunction therewith

ABSTRACT

A multi-mode digital photography method including generating an output image of a location L at a specific time t which is identified as a function of a user-selected photography task. the method including generating an output image of a particular scene which is built up from a plurality of images thereof, as another function of a user-selected photography task.

FIELD OF THE INVENTION

The present invention relates to apparatus and methods for digitalphotography.

BACKGROUND OF THE INVENTION

A wide variety of digital cameras is currently available. Conventionaldigital photography options and methods are described e.g. in the manualof the Sony DSC-T7 digital camera.

U.S. Pat. No. 5,774.591 to Black et al describes an apparatus and methodfor recognizing facial expressions and applications therefor.

The disclosures of all publications mentioned in the specification andof the publications cited therein are hereby incorporated by reference.

SUMMARY OF THE INVENTION

The present invention seeks to provide an application-specific digitalcamera and methods useful therefor.

There is thus provided, in accordance with a preferred embodiment of thepresent invention, a digital photography method comprising receiving adefinition of a moment at which an anticipated event is to photographed,using a digital imaging device residing in a digital camera to generatea stream of digital images of a location at which tile event isanticipated to occur; and inspecting the stream of digital images, toanticipate the moment in the stream, and to generate a trigger timed andconstructed to trigger generation of an image of the location at themoment.

Also provided, in accordance with a preferred embodiment of the presentinvention, is a digital photography system operative in conjunction witha digital imaging device, the system comprising a moment definitioninput device defining a moment at which an anticipated event is tophotographed, a stream of digital images, generated by the digitalimaging device, of a location at which the event is anticipated tooccur, and a moment anticipator operative to inspect the stream ofdigital images, to anticipate the moment in the stream, and to triggergeneration of an image of the location at the moment.

Further in accordance with a preferred embodiment of the presentinvention, the moment anticipator resides on an integrated circuit, thesystem also comprising a digital imaging device operative to generatethe stream and operative in conjunction with the integrated circuit.

Also provided, in accordance with another preferred embodiment of thepresent invention, is a digital photography method comprising receivinga definition of a moment at which an anticipated event is tophotographed, using a digital imaging device residing in a digitalcamera to generate a stream of digital images of a location at which theevent is anticipated to occur; and inspecting the stream of digitalimages, to detect, in the stream. a digital image which has captured themoment and selectively 30 storing the digital image which has capturedthe moment. Also provided, in accordance with a preferred embodiment ofthe present invention, is a digital photography system operative inconjunction with a digital imaging device, the system comprising amoment definition input device defining a moment at which an anticipatedevent is to photographed, a stream of digital images of a location atwhich the event is anticipated to occur; and a moment-catching imageselector operative to inspect the stream of digital images, to detect.in the stream, a digital image which has captured the moment and toselectively store the digital image which has captured the moment.

Further in accordance with a preferred embodiment of the presentinvention, the moment-catching image selector resides on an integratedcircuit, the system also comprising a digital imaging device operativeto generate the stream and operative in conjunction with the integratedcircuit.

Further in accordance with a preferred embodiment of the presentinvention, the definition of the moment comprises a definition of atleast one target state of at least one corresponding target object andwherein the moment comprises a moment at which at least one targetobject is in the at least one target state.

Still further in accordance with a preferred embodiment of the presentinvention, the target state comprises a target location and wherein themoment comprises a moment at which the target object has reached thetarget location.

Further in accordance with a preferred embodiment of the presentinvention, the target object comprises a race participant and the targetlocation comprises a finish line.

Still further in accordance with a preferred embodiment of the presentinvention the target object comprises an animal or human subject and thetarget location comprises a user-selected location.

Further in accordance with a preferred embodiment of the presentinvention, the target object comprises a diver and the target locationcomprises a location along an expected trajectory of a dive.

Still further in accordance with a preferred embodiment of the presentinvention, the definition of the moment comprises a definition of atarget state of a target object and wherein the moment comprises amoment at which the target object is in the target state.

Further in accordance with a preferred embodiment of the presentinvention, the target state comprises a target location and wherein themoment comprises a moment at which the target object has reached thetarget location.

Additionally in accordance with a preferred embodiment of the presentinvention, the target object comprises a race participant and the targetlocation comprises a finish line.

Still further in accordance with a preferred embodiment of the presentinvention, the target object comprises an animal or human subject andthe target location comprises a user-selected location.

Further in accordance with a preferred embodiment of the presentinvention, the target object comprises a diver and the target locationcomprises a location along an expected trajectory of a dive.

Still further in accordance with a preferred embodiment of the presentinvention, the target state comprises a state at which the targetobject's level of motion is locally maximal.

Additionally in accordance with a preferred embodiment of the presentinvention, the target state comprises a state at which the targetobject's level of motion is locally minimal.

Still further in accordance with a preferred embodiment of the presentinvention, the step of receiving a definition of a moment comprisesreceiving an indication that a user wishes to photograph candles beingblown out and wherein the target object comprises candle flames.

Further in accordance with a preferred embodiment of the presentinvention, the target object comprises an active subject.

Still further in accordance with a preferred embodiment of the presentinvention, the target state comprises a state at which the targetobject's level of motion is locally maximal.

Further in accordance with a preferred embodiment of the presentinvention, the target state comprises a state at which the targetobject's level of motion is locally minimal.

Further in accordance with a preferred embodiment of the presentinvention, the step of receiving a definition of a moment comprisesreceiving an indication that a user wishes to photograph candles beingblown out and wherein the target object comprises candle flames.

Additionally in accordance with a preferred embodiment of the presentinvention, the target object comprises a subject with moving limbs.

Further in accordance with a preferred embodiment of the presentinvention, the target object comprises a face and the target statecomprises a facial expression.

Further in accordance with a preferred embodiment of the presentinvention, the facial expression comprises a non-blinking expression inwhich the subject is not blinking.

Still further in accordance with a preferred embodiment of the presentinvention, the step of inspecting comprises anticipating a non-blinkingexpression and ensuring generation of a non-blinking image by generatingthe trigger upon detection of a blink so as to generate the non-blinkingimage before a subsequent blink.

Additionally in accordance with a preferred embodiment of the presentinvention, the facial expression comprises a smile.

Further in accordance with a preferred embodiment of the presentinvention, the facial expression comprises a surprised expression.

Still further in accordance with a preferred embodiment of the presentinvention, the target object comprises a face and the target statecomprises a facial expression.

Further in accordance with a preferred embodiment of the presentinvention, the facial expression comprises a non-blinking expression inwhich the subject is not blinking.

Still further in accordance with a preferred embodiment of the presentinvention, the facial expression comprises a smile.

Additionally in accordance with a preferred embodiment of the presentinvention, the facial expression comprises a surprised expression.

Also provided, in accordance with a preferred embodiment of the presentinvention, is a digital photography method comprising analyzing a streamof digital images of a scene and generating an output image of the sceneby performing a local image processing operation selectively on aportion of an image of the scene, the portion comprising an image ofless than the entirety of the scene.

Further in accordance with a preferred embodiment of the presentinvention, the scene includes moving objects and a background andwherein the local image processing operation comprises an operation ofreplacing images of moving objects with images of the background theobjects are obscuring.

Still further in accordance with a preferred embodiment of the presentinvention, the generating step comprises inspecting a plurality ofcandidate images of a portion of the scene and selecting an individualcandidate image from among the plurality of candidate images which islikely to represent the background.

Further in accordance with a preferred embodiment of the presentinvention, the selecting step employs at least one of the followingselection criteria: the duration of occurrence of an individualcandidate image, and the extent to which the individual candidate imagematches adjacent candidate images.

Still further in accordance with a preferred embodiment of the presentinvention, the local image processing operation comprises a noisereduction operation.

Still further in accordance with a preferred embodiment of the presentinvention, the noise reduction operation is performed differentially onportions of the image such that the extent of noise reduction is adecreasing function of the level of change within the portions.

Additionally in accordance with a preferred embodiment of the presentinvention, the noise reduction operation is performed selectively, onlyon portions of the image in which there is only a minimal level ofchange.

Also provided, in accordance with a preferred embodiment of the presentinvention, is digital camera apparatus comprising a digital imagingdevice operative to generate a plurality of preliminary digital imagesof a scene defining a plane; a noise reduction processor operative togenerate from the plurality of preliminary digital images, an outputimage of the scene with a reduced amount of noise, the noise reductionprocessor comprising an image aligner which uses image processing togenerate a plurality of aligned digital images from the plurality ofpreliminary digital images by laterally and rotationally aligning theplurality of preliminary digital images about an axis of rotationdisposed perpendicular to the plane of the scene.

Additionally provided, in accordance with a preferred embodiment of thepresent invention, is self-photography apparatus comprising: a digitalimaging device generating a stream of images of a location; and aself-photography analysis and control unit operative to perform imageprocessing on at least a portion of the stream of images of a locationin order to identify a moment at which an image of the location willcomprise a successful self-photograph of a photographer's self at thatlocation.

Further in accordance with a preferred embodiment of the presentinvention, the self-photography analysis and control unit is operativeinitially, to identify a photographer's arrival at the location andsubsequently, to identify that the photographer is now motionless at thelocation.

Further provided, in accordance with a preferred embodiment of thepresent invention. is a digital photography system comprising: a digitalimage stream analyzer operative to analyze a stream of digital images ofa scene; and a local image processing output image generator operativeto generate an output image of the scene by performing a local imageprocessing operation selectively on a portion of an image of the scene,the portion comprising an image of less than the entirety of the scene.

Additionally provided, in accordance with a preferred embodiment of thepresent invention, is a digital photography method comprising:generating a plurality of preliminary digital images of a scene defininga plane; generating from the plurality of preliminary digital images, anoutput image of the scene with a reduced amount of noise, including useof image processing to generate a plurality of aligned digital imagesfrom the plurality of preliminary digital images by rotationallyaligning the plurality of preliminary digital images about an axis ofrotation disposed perpendicular to the plane of the scene.

Further provided, in accordance with a preferred embodiment of thepresent invention, is a method for self photography comprisinggenerating a stream of images of a location; and performing imageprocessing on at least a portion of the stream of images of a locationin order to identify a moment at which an image of the location willcomprise a successful self-photograph of a photographer's self at thatlocation.

Additionally provided, in accordance with a preferred embodiment of thepresent invention, is a multi-mode digital camera apparatus comprisingdigital imaging apparatus operative to generate an output image of alocation L at a time t; and a time identifier operative to identify timet as a function of a user-selected photography task.

Further in accordance with a preferred embodiment of the presentinvention, the time identifier is operative to anticipate time t and totrigger operation of the digital imaging apparatus at time t.

Still further in accordance with a preferred embodiment of the presentinvention, the time identifier is operative to select, within a streamof digital images generated by the digital imaging apparatus, an imagegenerated at time t.

Further provided, in accordance with a preferred embodiment of thepresent invention, is a multi-mode digital photography method comprisinggenerating an output image of a location L at a time t, and identifyingtime t as a function of a user-selected photography task.

Still further in accordance with a preferred embodiment of the presentinvention, the image processing identifies a moment at which thephotographer has completed at least one of the following actions:

-   -   a. has reached location L;    -   b. has become generally motionless; and    -   c. has smiled.

Additionally in accordance with a preferred embodiment of the presentinvention, the moment definition input device generates a definition ofthe moment which comprises a definition of at least one target state ofat least one corresponding target object and wherein the momentcomprises a moment at which at least one target object is in the atleast one target state.

Further in accordance with a preferred embodiment of the presentinvention, the moment definition input device generates a definition ofthe moment which comprises a definition of a target state of a targetobject and wherein the moment comprises a moment at which the targetobject is in the target state.

Still further in accordance with a preferred embodiment of the presentinvention, the scene includes moving objects and a background andwherein the local image processing operation comprises an operation ofreplacing images of moving objects with images of the background theobjects are obscuring.

According to a preferred embodiment of the present invention, aphotography option is provided in which only the background of a sceneappears in a final photography product, without people or vehicles orother moving identities which temporarily obscure portions of the scene.

According to another preferred embodiment of the present invention, anight or low illumination photography option is provided in which noisedue to long exposure time, is reduced. This is preferably done by imageaveraging with factoring out of camera motion and moving objects whichoccur in the course of the various images which are generated during thelong exposure time and combined.

Also provided is image generation apparatus for use in conjunction witha digital imaging device, the apparatus comprising any of the aboveembodiments, minus the digital imaging device and/or minusfunctionalities such as memory provided within a conventional digitalimaging device. Each of the above embodiments may be coupled to orassociated with or used in conjunction with, a conventional digitalcamera or other digital imaging device.

The term “digital imaging device” or “digital camera” is intended toinclude any imaging device which generates, inter alia, a digitalrepresentation of a scene such as but not limited to a digital camera, aCCD array and associated digitizer, a CMOS detector, and any personaldevice that includes a digital camera such as a cellular phone orhand-held device which has digital-photographic functionality.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated from thefollowing detailed description, taken in conjunction with the drawingsin which:

FIG. 1 is a simplified pictorial illustration of a digital camera systemconstructed and operative in accordance with a preferred embodiment ofthe present invention.

FIGS. 2A-2L are simplified pictorial illustrations of the camera systemof FIG. 1 after selection of an individual option by the user;

FIG. 3 is a simplified functional block diagram illustration of thedigital photography system of FIG. 1, constructed and operative inaccordance with a preferred embodiment of the present invention;

FIG. 4 is a simplified pictorial illustration of a timeline suitable forany of the “catch the moment” applications in which moment anticipationfunctionality described herein is operational;

FIGS. 5A and 5B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 3;

FIG. 6 is a pictorial and time-line diagram illustrating an example ofthe operation of the object-at-location analysis and control unit 310 ofFIG. 3, according to a preferred embodiment of the present invention;

FIG. 7 is a simplified functional block diagram illustration of theobject-at-location analysis and control unit 310 of FIG. 3, constructedand operative in accordance with a preferred embodiment of the presentinvention;

FIGS. 8A and 8B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 7;

FIGS. 9A and 9B. taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus of themoving object detection 700 of FIG. 7;

FIG. 10 forms a simplified flowchart illustration of a preferred methodof operation for the filtering unit 720 of FIG. 7, which is operative tofilter out all moving objects not of interest;

FIG. 11 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the time of arrival estimator 730 ofFIG. 7;

FIG. 12 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the selector 790 of FIG. 7;

FIG. 13 is a pictorial and time-line diagram illustrating an example ofthe operation of the high/low motion analysis and control unit 320 ofFIG. 3, according to a preferred embodiment of the present invention;

FIG. 14 is another pictorial and time-line diagram illustrating anexample of the operation of the high/low motion analysis and controlunit 320 of FIG. 3, according to a preferred embodiment of the presentinvention;

FIG. 15 is a simplified functional block diagram illustration of thehigh/low motion analysis and control un it 320 of FIG. 3, constructedand operative in accordance with a preferred embodiment of the presentinvention;

FIGS. 16A and 16B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 15;

FIG. 17 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the motion level threshold unit 1530of FIG. 15;

FIG. 18 is a graph of motion level vs. time, useful in determining anappropriate time at which to trigger imaging and/or save an image, inlow motion detection applications;

FIG. 19 is a pictorial and time-line diagram illustrating an example ofthe operation of the facial features analysis and control unit 330 ofFIG. 3, according to a preferred embodiment of the present invention;

FIG. 20 is a simplified functional block diagram illustration of thefacial features analysis and control unit 330 of FIG. 3, constructed andoperative in accordance with a preferred embodiment of the presentinvention;

FIG. 21 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus ol FIG. 20;

FIG. 22 is a simplified functional block diagram illustration of thebackground building analysis and control unit 340 of FIG. 3, constructedand operative in accordance with a preferred embodiment of the presentinvention;

FIGS. 23A and 23B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 22;

FIG. 24 is a pictorial and time-line diagram illustrating an example ofthe operation of the background building analysis and control unit 340of FIG. 3, according to a preferred embodiment of the present invention;

FIG. 25 is a simplified functional block diagram illustration of thesub-image analyzer 2240 of FIG. 22, constructed and operative inaccordance with a preferred embodiment of the present invention;

FIG. 26 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the sub-image variability test unit2500 of FIG. 25;

FIG. 27 is a simplified functional block diagram illustration of thecandidate list update unit 2510 of FIG. 25, constructed and operative inaccordance with a preferred embodiment of the present invention;

FIG. 28 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of FIG. 27;

FIG. 29 is a simplified functional block diagram illustration of thecandidate list selector 2520 of FIG. 25, constructed and operative inaccordance with a preferred embodiment of the present invention;

FIG. 30 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of FIG. 29;

FIG. 31 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of the background image analyzer 2260 ofFIG. 22;

FIG. 32 is a cartoon illustration of an example of an urban scene inwhich three persons are strolling by. obstructing the scenic background;

FIG. 33 is a pictorial and time-line diagram illustrating an example ofthe operation of the noise reduction analysis and control unit 350 ofFIG. 3, according to a preferred embodiment of the present invention;

FIG. 34 is a simplified functional block diagram illustration of thenoise reduction analysis and control unit 350 of FIG. 3, constructed andoperative in accordance with a preferred embodiment of the presentinvention;

FIGS. 35A and 35B, taken together. form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 34;

FIG. 36 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “activechild” mode;

FIG. 37 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “birthdaycake” mode;

FIG. 38 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “don'tblink” mode;

FIG. 39 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “dive” mode;

FIG. 40 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “urban”mode;

FIG. 41 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “night”mode;

FIG. 42 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “race” mode;

FIG. 43 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “child/petrunning” mode;

FIG. 44 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “smile”mode;

FIG. 45 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “surprise”mode; and

FIGS. 46A-46B, taken together. form a simplified flowchart illustrationof a preferred method of operation for the apparatus of FIG. 3 whenphotographing in “self-photo” mode.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a simplified pictorial illustration of a digital camera systemconstructed and operative in accordance with a preferred embodiment ofthe present invention including a display of a plurality of photographyoptions 200 which the digital camera system of FIG. 1 provides for auser when s/he presses on menu button 230. As shown, a manual option isprovided which, if selected, enables the user to photograph as isconventional using state of the art digital camera systems. Theremainder of the options 200 guide the user in his photography effortsin a plurality of different situations, such as photographing an activechild, photographing an individual blowing out candles on a birthdaycake, photographing a portrait of a person while s/he is not blinking,photographing a dive e.g. into a body of water, photographing an urbanscene including moving people, cars and other objects which are not ofinterest, photographing a night scene without allowing the low level ofillumination to generate a high noise level, photographing the winningmoment of a race, photographing a child or pet running up to a givenpoint, photographing a person while s/he is smiling, photographing aperson as s/he is surprised, and photographing ones self. It isappreciated that option selection may be effected via any desirable userinterface device such as a menu or special button and the display ofFIG. 1 is provided merely by way of example.

The system of the present invention is operative generally to provide aplurality of modes within which the imaging device is guided to operate.The modes are operative to automatically shape the imaging process so asto provide the optimal photography product for each situation or option.For example, if the “active child” option is selected, the imagingdevice is guided to image an active child when his level of activitydiminishes to a level low enough to allow an unblurred image. If the“birthday cake” option is selected, the imaging device is guided toimage the child at the moment s/he extinguishes the candles e.g. byanalyzing previous images to detect flame motion. If the “don't blink”option is selected, the imaging device is guided to image the subject ata moment in which s/he is not blinking e.g. by detecting facialindications that the subject is about to blink and trigger imagingaccordingly. If the “dive” option is selected, the imaging device may beguided to image a diver or jumper as s/he hits the water.

If the “urban” option is selected, the imaging device may be guided toimage scenery unobscured by moving cars, people or other objects, bydigitally “erasing” the cars and/or people and/or objects. If the“night” option is selected, the imaging device is guided toautomatically reduce noise resulting from the long exposure timerequired for night photography. If the “race” option is selected, theimaging device is guided to image at the moment when it is detected, oranticipated, that an object (the winner) is crossing the finish line. Ifthe “child/pet running” option is selected, the imaging device is guidedto image at the moment when it is detected, or anticipated, that anobject (the child or pet) is arriving at a location at which the userhas pointed his or her camera. If the “smile” or “surprise” option isselected, the imaging device is guided to image at the moment when asmile or surprised expression is detected or anticipated to occur. Ifthe “self-photography” option is selected, the imaging device is guidedto image only after the self-photographer has reached a target location,has settled herself motionless at that location and, optionally, hassmiled.

It is appreciated that the system of the present invention need notprovide a separate mode for each option. Instead, it is possible toprovide a single mode serving or supporting several options, whereinthat mode is parameterized to allow each separate option to beimplemented as appropriate.

For example, an “object at location” mode may be provided tooperationalize each of the following options: dive, race, child/petrunning and self-photo. The “object at location” mode is constructed andoperative to image a location when an object arrives thereat. A“high/low motion” mode may be provided to operationalize each of thefollowing options: active child, birthday cake, and self-photo. Thismode is constructed and operative to image a subject when the level ofmotion is appropriate (low or high: low for an active child, to preventblurring; high for birthday cake candles, to identify the moment atwhich the candle flames are flickering out, and low for self-photo, toidentify the moment at which the self-photographer has settled himselfat the photography location). A “facial recognition[ mode may beprovided to operationalize each of the following options: don't blink,smile, surprise and optionally self-photography. This mode isconstructed and operative to image a subject when his facial expressionis appropriate for imaging i.e. in the “don't blink”, smile and surpriseoptions respectively, when the subject is not blinking, or smiling, orhas assumed a surprised expression.

A “noise reduction” mode may be provided to operationalize the nightphotography option. This mode is constructed and operative, under the“night” option described herein. to combine several images of a poorlyilluminated scene, while idenitifying and discarding noise. A“background” mode may be provided to operationalize the urban option.This mode is constructed and operative, under the “urban” optiondescribed herein, to combine several images of a scene, characterized inthat each portion of the scene is visible in at least one of the imagesbut typically not in all of them.

It is appreciated that more than one mode of operation may be used tooperationalize a single option. For example, self-photo tasks may beoperationalized by using the system's “object at location” mode toidentify that the self-photographer has reached the photography locationand by subsequently using the system's “low motion” mode to identifythat the self-photographer has arranged himself and is now sittingstill. Optionally. the self-photo task may subsequently use the system's“smile” option (“facial recognition” mode) to identify that theself-photographer is smiling.

Preferably, the user is entitled to select or define a logicalcombination of the options provided by the system of FIG. 1, forexample, the user might define Active Child AND Don't Blink if s/hewishes to photograph an active child while s/he is not blinking. Anotherexample is that the user might define Urban OR Race if s/he wishes, viaa single process of definition on his part, to generate two pictures ofa race scene including a picture of the winner reaching the finish lineand a picture of the backdrop of the race in which the runners and othermoving objects have been filtered out. Typically, these logicalcombinations are implemented, in the system, simply by defining eachspecific logical combination as a separate option to be supported by thesystem.

Preferably, the user is entitled to select or define a logicalcombination of different configurations for a single mode provided bythe system of FIG. 1, for example the user might define to photographthe first object arriving at a location such as a finish line OR thesecond object arriving at the location OR the third object arriving atthe location if s/he wishes to photograph all three medal-winningathletes finishing an official race.

Preferably, the user is able to select some modes with a simple logicrelation between them like ‘and’, ‘or’ and ‘not’. For example,photograph an active child when s/he is not blinking; or generate twoimages of the same scene: the urban background thereof and an image of acar that crosses a line in the viewed scene.

Different modes of operation need not be constructed and operativeindependently of one another. Instead, preferably, the system of thepresent invention includes a “catch the moment” function and a “scenebuilding” function and the modes described above are constructed andoperative within one or another of these functions.

The “catch the moment” function is a group of functionalities relevantto applications in which a particular scene is to be imaged at aparticular time. The group of functionalities may for example include amoment anticipator functionality, operative to predict the time at whichan application-specific change will occur in the scene. Thisfunctionality is useful for many applications in which a scene is to beimaged at a particular time. Another functionality useful for manyapplications in which a scene is to be imaged at a particular time is amoment selection functionality operative to identify an image within anexisting stream of images, with predetermined characteristics.Typically, the object at location, high/low motion and facialrecognition modes are each constructed and operative within the “catchthe moment” function.

The “scene building” function is a group of functionalities relevant toapplications in which a particular scene is to be built up from aplurality of images thereof. Typically, the noise reduction andbackground modes are each constructed and operative within the “scenebuilding” function. The “scene building” group of functionalities mayfor example include a sub-image separator functionality, a sub-imageanalyzer functionality, a scene image generator functionality and ascene analyzer functioniality.

It is appreciated that the above photography options are merelyexemplary of the essentially limitless number of special photographysituations which may be defined and supported by suitable programmingwhich adapts the operation of the camera, automatically, to theparticular characteristics of the particular photography situation.Categories of such photography situations may be defined to include anumber of photography options which have similar characteristics. Forexample, a photography system of the present invention may include“catch the moment” photography options, such as but not limited to theactive child, birthday cake, blink, dive, race, child/pet running,smile, surprise and self-photo options, in each of which it is desiredto photograph a specific moment having known image characteristics whichcan either be anticipated, in which case the operation of the camera istimed accordingly, or selected, in which case a sequence of images maybe discarded, but for a single image selected at the appropriate time.

As another example, a photography system of the present invention mayinclude “scene building” photography options, such as but not limited tothe urban and night options, described herein, in each of which it isdesired to build an image of a scene using local image processingmethods applied to the images arriving from the digital imaging device10.

FIG. 2A-2L are simplified pictorial illustrations of the camera systemof FIG. 1 after selection of an individual option by the user, at whichpoint the system typically provides the user with instructions as to howto photograph within the selected option. It is appreciated that theparticular messages shown and described herein are merely examples. Inaddition to or instead of the voice, a text message can appear on thescreen or any other mode of message presentation may be employedincluding presentation within a user manual.

If the “manual”0 option is selected, as shown in FIG. 2A, there is nomessage or a minimal message to the user who then proceeds to photographwithout intervention or special set-up by the camera system of FIG. 1other than as is known in the art.

If the “active child” option is selected, as shown in FIG. 2B, themessage to the photographer may be: “Position your child at a desiredlocation, point the camera at the child, press the shutter button andkeep the camera still until you hear a beep”.

If the “birthday cake” option is selected, as shown in FIG. 2C, themessage may be: “Point the camera at the flames of the candles, pressthe shutter button and keep the camera still until you hear a beep”.

If the “don't blink” option is selected, as shown in FIG. 2D, themessage may be: Point the camera at your subject's face, press theshutter button and keep the camera still until you hear a beep”.

If the “dive” option is selected, as shown in FIG. 2E, the message maybe: “Point the camera at the airspace in front of the diving board or atthe water beneath the diving board. Press the shutter button and keepthe camera still until you hear a beep”.

If the “urban” option is selected, as shown in FIG. 2F, the message maybe: “Point the camera at your urban scene. Don't worry about people orcars obstructing the scene. Your camera will erase them for you. Pressthe shutter button and keep the camera still until you hear a beep. Bepatient-this may take a while.”

If the “night” option is selected, as shown in FIG. 2G, the message maybe: “Point the camera at your night scene. Press the shutter button andkeep the camera still until you hear a beep. Be patient-this may take awhile.”

If the “race” option is selected, as shown in FIG. 2H, the message maybe: “Point the camera at the finish line. Press the shutter button andkeep the camera still until the race is over and you have heard aconfirming beep.”

If the “child/pet running” option is selected, as shown in FIG. 21, themessage mav be: “Choose a location. The camera will photograph yoursubject as it runs by this location. Point the camera at this location,Press the shutter button and keep the camera still until you hear abeep”.

If the “smile” option is selected, as shown in FIG. 2J, the message maybe: “Point the camera at your subject's face. Press the shutter buttonand keep the camera still until you hear a beep”.

If the “surprise” option is selected, as shown in FIG. 2K, the messagemay be: “Point the camera at your subject's face. Press the shutterbutton and keep the camera still until you hear a beep”.

If the “self-photo” option is selected, as shown in FIG. 2L, the messagemay be: “Choose a location. Point the camera at your location and pressthe shutter button. Walk to your location, stand still (optional, andsmile) until you hear a beep.”

FIG. 3 is a simplified functional block diagram illustration of thedigital photography system of FIG. 1, constructed and operative inaccordance with a preferred embodiment of the present invention. Thedigital imaging device 10 may comprise digital imaging apparatus similaror identical to that provided within any suitable digital camera such asthe following state of the art digital camera: SONY DSC-T7, OlympusC-8080 or Canon PowerShot SD500.

As shown, a plurality of imaging analysis and control units 310, 320,330, 340 and 350 are preferably provided to carry out a correspondingplurality of photography task types differentially, as a function of theknown characteristics of each photography task type e.g. each of theexample options shown in FIG. 1. A selector 100 selects one of these asa function of a user selected option. as shown in FIG. 1, andoptionally, other input data as shown. Each option preferably isassociated with a configuration stored in configuration database 70. Theconfiguration determines e.g., definition of camera response time. atunit 50.

According to a preferred embodiment of the present invention, a sceneimaging, analysis, creation and control functionality is provided whichis operative to carry out photography tasks in which it is desirable tocombine a plurality of images into a single final image e.g. as in nightphotography and as in urban scene photography in which moving objectsobscure various portions of a backdrop in various different scenes. Amoment anticipation functionality may be provided to carry outphotography tasks in which it is necessary and possible to anticipate aparticular moment at which imaging should take place, long enough beforethat moment to enable activation of the imaging process. e.g. 0.1-5seconds before the imaging process is to be activated. An example ofsuch a task is photographing the winning moment in a race. A momentselection imaging analysis and control functionality may be provided tocarry out photography tasks in which it is desired to select an imagefrom a stream of images, immediately but retroactively. If flash isused, for example, the moment selection functionality is typically notappropriate whereas the moment anticipation functionality is appropriatebecause it enables the flash to be activated at the exact moment atwhich imaging is supposed to occur. If a baby randomly waving her armsand legs is imaged, for example. the moment selection functionality maybe appropriate because the child's movements are not easily predictablesuch that the moment anticipation functionality may not be able tooperate effectively.

As shown, selector 100 selects the appropriate one of the imaging,analysis and control units depending on the photography task. Typically,digital imaging parameters provided by the digital imaging device 10parameterize each photography task to allow the selector 100 to performits selection function appropriately. It is appreciated that thespecific imaging analysis and control units shown are merely exemplaryof the possible different units which may be provided in any suitablecombination.

The live image stream generated by the digital imaging device need notbe at conventional video sampling rate and may, for example, be withinthe range of 2-120 images per second.

If the only imaging analysis and control device provided is based onmoment anticipation functionality, a lower resolution stream may beemployed such as a stream of hall the requested photo resolution sincedigital imaging device 10 is the unit which feeds the final image intomemory. If moment selection functionality is used, full resolution (asset by the user via digital imaging device 10) is typically providedsince the analysis and control unit feeds the final image into memory80.

If the bandwidth from digital imaging device 10 to selector 100 islimited, the resolution may be reduced in anticipation, while increasingthe stream rate.

It is appreciated that at least one of the units 30, 50, 70, 80, 100,310, 320, 330, 340 and 350 may reside on an integrated circuit or a chipconstructed and operative to reside within digital camera housing.Alternatively, these may be provided within a small external device e.g.card which may be operatively associated with a digital camera. Anotheralternative is that at least one of the functional units (30, 50, 70,80, 100, 310, 320, 330, 340 and 350) may be retrofit onto an existingintegrated circuit or chip, such as a programmable CPU. forming part ofan existing digital camera system.

According to another preferred embodiment of the present invention, anexternal device such as a personal computer is provided, that mayreceive the images and the option type from an input device such as theinput device of FIG. 1. The camera may save only the option type to itsmemory, and an external device may read the option type along withimages arriving from the memory of digital imaging device 10 and mayperform the image selection or scene creation functions. The results maybe saved in the external computer or in the memory of the digitalimaging device 10, and the images which are not required or were notselected may be, but need not be, erased or allowed to be overridden

The units 310, 320, 330, 340 and 350 can each be a separate integratedcircuit or a chip or alternatively, some or all of these may beimplemented on one chip or integrated circuit.

If moment selection functionality or scene building functionality areselected and units 310 or 320 or 330 or 340 or 350 operate relativelyslowly, e.g. for “heavy” applications, the stream generated by digitalimaging device 10 may be a delayed stream. For example, the digitalimaging device 10 may save some images and then recall them from memoryand transmit them as a stream to the selected unit.

It is appreciated that the final image memory of FIG. 3, which storesthe output photograph, need not be separate from the memory of digitalimaging device 10 and instead may be integral therewith. It isappreciated that, when the moment selection functionality of the presentinvention is employed, memory 80 may save not only a final image butrather substantially all images from the live image stream generated bydigital imaging device 10. A final image may then be selected by meansof a keep command issued by a selected one of the analysis and controlunits. For all images other than the final image, the selected analysisand control unit typically issues an override command rather than a keepcommand.

The selector 100 simply stores the relevant unit 310, 320, 330, 340 or350 for each of the options supported e.g. each of the optionsillustrated in FIG. 1.

It is appreciated that more than one level of photography situations maybe defined by the photography task-specific camera system of the presentinvention. For example, the display 210 of FIG. 1 may include an“advanced” button 220 which, if selected, opens a menu. e.g. on display210, as shown in FIG. 1. The user may be invited to select one of aplurality of modes such as object at location, high/low motion, facialrecognition, noise reduction, and background. The modes may include anyor all of the following:

Object at location: Photographing a defined object as it reaches adefined location, or photographing the first or n'th object to reachthat location.

High/low motion: Photographing a moving object at a moment of zero orlocally minimal motion, or at a moment of locally maximal motion.

Facial recognition: Photographing a subject at a moment at which hisfacial expression corresponds to a predefined description.

Noise reduction: Reducing noise resulting from long exposure time e.g.for night photography situations, even for photography situations inwhich substantial camera motion and/or motion of objects within thescene are present.

Background: Photographing a background obscured by moving objects,including filtering the moving objects out of the eventual image.

It is appreciated that the apparatus and methods shown and describedherein are useful not only in a conventional digital camera system butalso in systems which include a digital photography component such ascellular telephones, personal digital assistants, and other hand-heldand personal devices having digital photography capabilities.

A camera response time determination unit 50 is operative to receiveinformation on the operation mode of the digital imaging device 10 fromthat device. For example, the digital imaging device 10 may provide unit50 which indications of whether or not its flash is operative, whetheror not its red-eye function is operative, and generally informationregarding any aspect of the digital imaging device 10's operation modewhich affects response time ΔT seconds.

Selector 100 receives ΔT from camera response time determination unit 50and sends it to the selected analysis and control units (310, 320, 330,340 or 350).

Typically, only analysis and control units that may carry out momentanticipation functionality (e.g. units 310, 320 or 330) use ΔT. Theseunits, when carrying out moment anticipation functionality, generate atrigger message indicating that the scene should be imaged ΔT secondsfrom the present time. The trigger message actuates the digital imagingdevice 10, at ΔT seconds from when the trigger is sent, e.g. as shown inFIG. 4.

FIG. 4 is a simplified pictorial illustration of a timeline suitable forany of the “catch the moment” applications which employ momentanticipation functionality described herein. As shown, a selected one ofthe analysis and control units 310, 320 or 330 may generate a triggerwhich activates the imaging device 10 to take picture at a best timee.g. at a moment at which a predetermined amount of time has elapsedfrom the moment of triggering.

FIGS. 5A and 5B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 3. In step 520, ΔT typically depends on flash, flash+red eye, andelectronic response time. Steps 535-540 in FIGS. 5A-5B form a streamloop which continues, including performance of all relevantcomputations, until one or more of the following events occur:

-   -   Trigger is sent (anticipation).    -   Final image generation announcement (selection+scene).    -   User intervention (such as another press on the shutter button).

As optional setup, the system may be operative to continue thecomputations of moment selection functionality or scene buildingfunctionality described in steps 800-820, 840 and 850 of FIGS. 8A and8B; steps 1600-1625, 1640 and 1645 of FIGS. 16A and 16B; steps 2100,2105, 2115 of FIG. 21; FIGS. 23A and 23B and FIGS. 35A and 35B, for aslong as the user continues to press on the shutter button even after afinal image generation announcement has been made (step 540).

FIG. 6 is a pictorial and time-line diagram illustrating an example ofthe operation of the object-at-location analysis and control unit 310 ofFIG. 3, according to a preferred embodiment of the present invention.FIG. 6 compares the operations of the moment anticipation functionalityof the present invention, the moment selection functionality of thepresent invention and conventional photography functionality, all for an“object at location” type application such as a race situation. Atime-lined cartoon of the race is shown in row I. Row II shows thenumber of time units (images) which remain until the subject crosses thefinish-line. In the illustrated embodiment, it is assumed that two timeunits are required to activate the imaging process. The imaging processmay be activated either by conventional shutter button pressing or by aninternal application specific imaging control message or “trigger”provided by a preferred embodiment of the present invention. As shown,conventional photography (row V) may result in post-facto imaging, afterthe race has already ended, imaging which uses moment anticipationfunctionality (row III) results in a single photo being generated at theright moment, and imaging which uses moment selection functionality (rowIV) results in saving images 410, 420 and 430 from among a stream ofsuch images, numbered respectively 400, 410, 420, 430, 440, 450, . . . .Each latter image may override each former image in memory. A finalimage generation announcement is sent to digital imaging device 10 reimage 430.

FIG. 7 is a simplified functional block diagram illustration of theobject-at-location analysis and control unit 310 of FIG. 3, constructedand operative in accordance with a preferred embodiment of the presentinvention. In FIG. 7, preferably, the user can set a “location mode”defining when an object of interest is to be imaged, as comprising anyof the following:

-   -   Reaching a specified area.    -   Crossing a specified line.    -   Comes closest to a given point.    -   Strays farthest from a given point.

It is appreciated that a user setting is not limited to the abovelocation modes but can be any other location based functions, e.g. itmay be desired to image an object when it strays maximally from aspecified line instead of when one of the above criteria occurs. Thelocation mode may also exist in the database 70.

It is appreciated that detection of an object in a specified location orin compliance with any suitable location criteria such as the above fourcriteria, need not be based on motion detection algorithm and insteadmay be based on other suitable methods such as tracking, segmentation orrecognition.

It is appreciated that an “object at location unit” need not photographan image using location data only and instead may be based on anylocation related object function, including velocity, direction,acceleration, trajectory type and more. Examples: photographing theobject at the maximum velocity imaging the object only When it is foundto be moving in a specified direction, or photographing the object atits minimal acceleration.

It is appreciated that an “object at location unit” need not photographbased only on location-related functions and alternatively or inaddition may be partly or wholly based on any object data function otherthan location-related characteristics, Such as photographing the objectof the maximum viewed size, maximum brightness, or photographing theobject whose color is closest to a predefined color such as red.

It is appreciated that an “object at location unit” need not use only asingle event for “triggerin” or “selection” but may use a pre-definedset or sequence or logical combination of events, such as arrival at twopoints in sequential order, or the following sequence of events: movingto the right, arriving at a point and then moving at highest velocity.

FIGS. 8A and 8B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 7. Regarding unit 840, it is appreciated that the saving decisionneed not use time-based criteria and instead may be based on othercriteria such as distance to specified location.

FIGS. 9A and 9B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus of themoving object detection 700 of FIG. 7. Alignment may be performed usingregistration which is based on template matching techniques, where thedisplacement of each template is determined by normalized correlation,and the alignment is determined by fitting a camera motion model totemplate results. Alternatively, alignment may be based on theregistration methods described in “Image Registration Methods: ASurvey”, Barbara Zitova, Jan Flusser. Imaging and Vision Computing 21(2003), pp. 977-1000 and publications referenced therein. All of theabove publications are hereby incorporated by reference. The imagewarping may use nearest neighbor interpolation, bilinear interpolationand other suitable interpolation methods. Regarding step 905, thealignment in the current embodiment is carried out in displacement (ΔX,ΔY) and in rotation (Δθ).

In step 905, it is appreciated that the alignment need not be based ondisplacement and rotation, instead it may be based on less, more orother parameters, such as affine alignment.

In step 915, it is appreciated that the reference image creation neednot use a weighted average and instead may be based on any other imageoperators and measures of central tendency such as a median betweenimages. In step 930, it is appreciated that the threshold computationneed not be based on histogram's standard deviation and instead may beconstant, based on any other histogram related function such as localminimum in the histogram, or an image related function. In step 945, itis appreciated that blob filtering need not filter only small blobs andinstead may filter any other non-interesting blobs, such as blobs withnon-interesting shape, color or brightness. In step 950, it isappreciated that the extraction of tracks from blobs need not usedistance-based blob matching and instead may be based on other methods.

It is appreciated that motion detection need not use difference basedalgorithms and instead may be based on other methods such as image flow.

FIG. 10 forms a simplified flowchart illustration of a preferred methodof operation for the filtering unit 720 of FIG. 7, which is operative tofilter out all moving objects not of interest.

FIG. 11 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the time of arrival estimator 730 ofFIG. 7. Regarding step 1100, it is appreciated that the estimation neednot use polynomial or function fit and instead may be based on othermethods. Also, the fit need not use least mean square method and insteadmay be based on other methods, such as minimum of maximal error.

FIG. 12 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the selector 790 of FIG. 7. Theselector implementation is typically the same for all analysis andcontrol units that have selectors.

FIG. 13 is a pictorial and time-line diagram illustrating an example ofthe operation of the high/low motion analysis and control unit 320 ofFIG. 3, according to a preferred embodiment of the present invention inwhich the unit is operating in low motion detection mode. The motionlevel threshold for anticipation and for selection is shown to beconstant, however in fact it may be changed during processing.

FIG. 13 compares the operations of the moment anticipation functionalityof the present invention, the moment selection functionality of thepresent invention and conventional photography functionality, all for“high/low motion” type applications operative to detect low motionspecifically, such as in an image of a hand-waving subject. A time-linedcartoon of the scene is shown in Row I. Row II shows the motion level ofthe image caused mainly by the waving hand, the motion level thresholdfor anticipation and the motion level threshold for image selection. Inthe illustrated embodiment. it is assumed that one time unit is requiredto activate the imaging process. The imaging process may be activatedeither by conventional shutter button pressing or by an internalapplication-specific imaging control message or “trigger” provided inaccordance with a preferred embodiment of the present invention. Asshown, conventional photography (row V) may result in a smeared imagecaused by the waving (1310). In contrast, imaging which uses momentanticipation functionality (row III) results in a single photo beinggenerated at the moment at which the hand wave is temporarily arrested,and imaging which uses moment selection functionality (row IV) resultsin saving of images 1330 and 1340 from among a stream of such images,numbered respectively 1300, 1310, 1320, 1330, 1340, 1350, . . . ,wherein each later image overrides its predecessors. A final imagegeneration announcement is sent to digital imaging device 10 at (for)image 1340.

FIG. 14 is another pictorial and time-line diagram illustrating anexample of the operation of the high/low motion analysis and controlunit 320 of FIG. 3, according to a preferred embodiment of the presentinvention in which the unit is operating in high motion detection mode.The motion level threshold for anticipation is typically the same as themotion level from selection. The motion level threshold is shownconstant however in fact it may be changed during processing.

FIG. 14 compares the operations of the moment anticipation functionalityof the present invention, the moment selection functionality of thepresent invention and conventional photography functionality, all for“high/low motion” type application operative to detect high motion suchas blowing out candles in a birthday cake scene. A time-lined cartoon ofthe scene is shown in row I. Row II shows the motion level of the imagecaused mainly by the flickering candle flames and the motion levelthresholds, combined for anticipation and selection. In the illustratedembodiment, it is assumed that one time unit is required to activate theimaging process. The imaging process may be activated either byconventional shutter button pressing or by an internalapplication-specific imaging control message or “trigger” provided by apreferred embodiment of the present invention. As shown, conventionalphotography (row V) may result in post-facto imaging, i.e. an imageafter the candles have already been extinguished (1440). Imaging whichuses moment anticipation functionality (row III) results in a singlephoto being generated at the precise moment at which the candles areblown out, and imaging which uses moment selection functionality (rowIV) results in saving of images 1420 and 1430 from among a stream ofsuch images, numbered respectively 1400, 1410, 1420, 1430, 1440, 1450, .. . , wherein each later image overrides its predecessors. A final imagegeneration announcement is sent to digital imaging device 10 at (for)image 1430.

FIG. 15 is a simplified functional block diagram illustration of thehigh/low motion analysis and control unit 320 of FIG. 3, constructed andoperative in accordance with a preferred embodiment of the presentinvention. In unit 1510, alignment may be based on the registrationmethods described in “Image Registration Methods: A Survey”, BarbaraZitova, Jan Flusser, Imaging and Vision Computing 21 (2003). pp.977-1000 and publications referenced therein. All of the abovepublications are hereby incorporated by reference.

FIGS. 16A and 16B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 15. In the following description, a low motion detectionapplication is assumed. Modification of the methods for high motiondetection appears in (parentheses). The aligner 1510, as described instep 1605 of FIG. 16A, may be operative in accordance with theprinciples of operation described above with reference to FIG. 9. Instep 1610, the coordinates of the processing window may be transformedusing the alignment data in order to process the same area even if thecamera is not exactly still.

In step 1635, the test of the local minimum (maximum) is for assuringthe photo has the minimal (maximal) motion level. If the minimum(maximum) is at ΔT, which is the start of the extrapolated data, themotion level would be lower (higher) before the actual photo. If theminimum (maximum) is at ΔT+ΔI, which is the end of the extrapolateddata, the motion level would be lower (higher) after the actual photo.In this case the photo is preferably taken of subsequent images.

In step 1645, If THR_(save)<=THR_(trig) (THR_(save)>=THR_(trig)), thistypically means that an image with motion level of THR_(trig) or less(more) was already saved.

In step 1600, the previous image memory may not store the previous imageonly but instead may store other previous images or a combined referenceimage to be used for motion level computation.

In step 1615, the motion level need not be based on image differencingbut instead may be based on other methods, such as image flow, orhistogram difference. It is appreciated that the motion level need notbe computed from two images but instead may use more images oralternatively only a single image. In the latter case, motion level canbe computed from the image smear, which may be computed, for example, bymeans of local contrast (e.g. measuring the average edge intensity in acomputed window).

In step 1630, the motion level extrapolation need not use second orderpolynomial fit, but instead may be based on other methods, such as fitto a general function.

It is appreciated that the aligner 1510 may be disabled to compute thecombined motion level of the camera and of the object within the entireprocessing area. In such a case the image is selected or triggered whenthe combined motion of the camera and the object is relatively low(high). This option is preferably also used to reduce or eliminate imagesmear caused by the camera motion.

FIG. 17 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the motion level threshold unit 1530of FIG. 15. The first threshold THR_(SAVE) is typically the minimum(maximum) motion level until current time. Image should typically besaved if its motion level is below (above) this value. For triggeringand announcement, the method of FIG. 17 may estimate if there is highprobability that the current motion level will be minimal (maximal)until maximum processing time. Therefore, it is based on statistics fromthe previous images.

It is appreciated that the thresholds need not use such statistics, andinstead may be constant. or based on other methods such as directcomputation of the expected minimum (maximum) motion level until themaximal computation time.

FIG. 18 is a graph of motion level vs. time, useful in determining anappropriate time at which to trigger imaging and/or save an image, inlow motion detection applications. The curve represents the motion levelas it changes over time. The diagonal patterned line represents themotion level threshold, THR_(TRIG). It typically has a non-zero valuestarting from point C, after there are enough frames for a statistic.Tile dotted line represents THR_(SAVE). In some periods, it is same asthe motion level.

At point A, the motion level is the minimum achieved until this point.Therefore, during the saving process an image will be saved in the finalimage memory 80. A final image generation announcement will not be sentsince it is the motion level is higher than the THR_(TRIG) (which iszero). For the same reason, no trigger will be sent in for theanticipation process. Similarly, for point B, saving is typicallycarried out but no announcement or trigger is generated. At point C,THR_(TRIG) has a non-zero value. In the saving process. a final imagegeneration announcement is typically sent since the motion level of thesaved image is lower than the threshold. In triggering, a trigger istypically not sent, since in the time region ΔT until ΔT+AI there is nolocal minima. At point E, the image capture trigger unit typicallydecides to send application specific control of triggered final image,since there is local minima (F), that is below THR_(TRIG) in the timeregion ΔT until ΔT+AI. The trigger is typically sent slightly after E,at time F−ΔT. In the saving process, if user keeps clicking on theshutter button, the image is typically saved in the final memory atpoint F, and final image generation announcement is typically resent. Atthe triggering process, application specific control of triggered finalimage is typically not sent since one was sent already. At point G, thesame occurs as at point F.

FIG. 19 is a pictorial and time-line diagram illustrating an example ofthe operation of the facial features analysis and control unit 330 ofFIG. 3, according to a preferred embodiment of the present invention. Inthis case ΔT is 2 stream-images long. Typically, when a featureextraction functionality, based on conventional image processing and/orfacial feature detection methods, first detects a small smile,application specific control of triggered final image is sent.

FIG. 19 compares the operations of the moment anticipation functionalityof the present invention, the moment selection functionality of thepresent invention and conventional photography functionality, all for“facial features” type application, such as a smiling person situation.A time-lined cartoon of the scene is shown in Row I. Row II shows thenumber of time units (images) which remain until the person smiles. Inthe illustrated embodiment, it is assumed that two time units arerequired to activate the imaging process. The imaging process may beactivated either by conventional shutter button pressing or by aninternal application specific imaging control message or “trigger”provided by a preferred embodiment of the present invention. As shown,conventional photography (row V) may result in post-facto imaging, afterthe person has stopped smiling (1950). Imaging which uses momentanticipation functionality (row III) results in a single photo beinggenerated at the right moment (i.e. during the smile), and imaging whichuses moment selection functionality (row IV) results in a singlesmile-containing photo or image 1930 being saved from among a stream ofsuch images. numbered respectively 1900, 1910, 1920, 1930, 1940, 1950, .. . .

FIG. 20 is a simplified functional block diagram illustration of thefacial features analysis and control unit 330 of FIG. 3, constructed andoperative in accordance with a preferred embodiment of the presentinvention.

FIG. 21 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of FIG. 20.

Detection of facial features at steps 2110 and 2115 may be carried outusing state of the art facial feature detection methods such as thosedescribed in the following publications, the disclosures of which arehereby incorporated by reference:

“Real-Time Facial Expression Recognition Based on Features' Positionsand Dimensions”. Hiroshi Sako and Anthony V. W. Smith, Proceedings ofthe 13th International Conference on Pattern Recognition, 1996, Volume3, 25-29 Aug. 1996 Page(s):643-648.

“Facial Expression Recognition Combined with Robust Face Detection in AConvolutional Neural Network”, Masakazu Matsugu, Katsuhiko Mori, YusukeMitari and Yuiji Kaneda. Proceedings of the International JointConference on Neural Networks, 2003. Volume 3, 20-24 July 2003Page(s):2243-2246

“Facial Expression Recognition Using Constructive Feedforward NeuralNetworks”, L. Ma and K. Khorasami, IEEE Transactions on Systems, Man andCybernetics Part B. Volume 34. Issue 3, June 2004 Page(s):1588-1595.

Detection of blinking at steps 2110 and 2115 may be performed usingstate of the art facial feature detection methods such as thosedescribed in the above-referenced Sako and Smith publication. In Sakoand Smith, the eye is located using detection of eyebrow and pupil. Ifonly the eyebrow is detected the eye is assumed to be blinking. Anothermethod is to check if the color below the eyebrow is same as the skincolor, in which case a blink is assumed to be occurring since the eyelidis apparently visible, or different, in which case a blink is assumednot to be occurring since the eye's pupil is apparently visible.

Since blinking is hard to anticipate at step 2110, especially when ΔT isabove ¼ second, a preferred selected moment to trigger the digitalimaging device is upon detection of blinking. At this time there is thehighest probability that the subject to be photographed will not blinkwithin a time interval of ΔT from the detected blink.

FIG. 22 is a simplified functional block diagram illustration of thebackground building analysis and control unit 340 of FIG. 3, constructedand operative in accordance with a preferred embodiment of the presentinvention. FIGS. 23A and 23B. taken together, form a simplifiedflowchart illustration of a preferred method of operation for theapparatus of FIG. 22. The aligner 2220, as described in step 2305 ofFIG. 23A, may be operative in accordance with the principles ofoperation described above with reference to FIG. 9.

Background image creation may be based on the following steps:

-   a. For each portion of the scene, there is a list of candidates,    i.e. sub-images to be considered for use as the background image of    this portion. For example, in a scene portion having a lawn in the    background and a moving red car in the foreground, candidates may    include green sub-images (corresponding to moments in which the red    car is not present), red sub-images (corresponding to moments in    which the red car is present) and other sub-images containing a    mixture of green and red (corresponding to moments in which the red    car is either in a state of arrival or in a state of departure).    Each candidate comprises a sub-image and related data.-   b. The method first fills in the candidate list using the data in    the input stream (from digital imaging device 10 of FIG. 3) and then    selects the best candidate for each portion.-   c. A candidate contains a sub-image that was extracted from an image    in the scene portion.-   d. For each candidate, the occurrence is computed, e.g. the number    of images containing the sub-image similar to the candidate    sub-image is counted. If the candidate has a high occurrence rate,    it is more apt to be used in the background image for the    corresponding portion.-   e. Another test for each candidate is the fit to the surrounding    background. If a candidate matches the background (its borders are    similar to the tangent pixels in the background image) it is more    apt to be used in the background image for the corresponding    portion.

Alignment in step 2305 may be based on the methods described above withreference to FIG. 9. In step 2310, a sub-image may be a portion of theimage, for example 8*8 pixels, the whole image or even only a singlepixel. In a preferred embodiment, the sub-images are arranged as a grid.However, alternatively, sub-images may be arranged in any suitablearrangement which may or may not overlap. Regarding step 2310, accordingto a preferred embodiment, the sub-images are square. However,alternatively, they may be any shape and may comprise a set of connectedor even unconnected pixels.

Regarding step 2300, the previous image memory need not store theprevious image only but instead may store other previous images or acombined reference image to be used for the alignment process.

In step 2320, the background image generator need not use imageplacement but instead may be based on other methods, such as imageaveraging.

FIG. 24 is a pictorial and time-line diagram illustrating an example ofthe operation of the background building analysis and control unit 340of FIG. 3, according to a preferred embodiment of the present invention.

FIG. 24 describes background image building for a scene with a house, aroad and a tree, while three moving persons obscure, at various times,various parts of the scene. A time-lined cartoon of the scene is shownin Row I, Row II shows the temporary background image in the backgroundimage memory 2270. As time goes on, the background image contains fewerand fewer moving objects until it eventually contains only thebackground scene. At image 2440, background image analyzer 2260concludes that the background image is adequate and sends it to thefinal image memory 80 while sending a final image generationannouncement to the digital imaging device 10.

FIG. 25 is a simplified functional block diagram illustration of thesub-image analyzer 2240 of FIG. 22, constructed and operative inaccordance with a preferred embodiment of the present invention. In thecurrent embodiment 3 candidates are assumed, by way of example, for eachsub-image. It is appreciated that the number of candidates may be 2 toinfinite.

FIG. 26 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of the sub-image variability test unit2500 of FIG. 25. Regarding step 2605, the variability need not use imagedifferencing but instead may be based on other methods such as imageflow or histogram difference. Regarding step 2605, the variability neednot use operation on the raw data of the images but instead may applyfilters, such as smoothing filter, or transforms, such as Fouriertransform, on the images before computing the variability. Regardingstep 2610, the threshold may not be constant but instead may be userconfigured or adaptive based on image content, such as proportional tothe average of the variability difference for all sub-images.

FIG. 27 is a simplified functional block diagram illustration of thecandidate list update unit 2510 of FIG. 25, constructed and operative inaccordance with a preferred embodiment of the present invention.

FIG. 28 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of FIG. 27. Regarding step 2805,similarity need not be based on image differencing but instead may bebased on other methods such as image flow or histogram difference.Regarding step 2805 similarity need not use an operation on the raw dataof the images but instead may apply filters, such as a smoothing filter,or transforms, such as a Fourier transform, on the images beforecomputing the similarity. Regarding step 2815, the threshold may not beproportional to the average of difference of previously matchsub-images, but instead may be based on other parameters, such as thestandard deviation of the difference. Also, the threshold may not bebased on the difference of previously matched sub-images, but insteadmay be based on other methods, such as proportionality to the contrastof the sub-image.

FIG. 29 is a simplified functional block diagram illustration of thecandidate list selector 2520 of FIG. 25, constructed and operative inaccordance with a preferred embodiment of the present invention.

FIG. 30 forms a simplified flowchart illustration of a preferred methodof operation for the apparatus of FIG. 29. Regarding step 3000, the fitneed not use difference between tangent pixels, instead it may be basedon other methods such as counting number of almost-same pixels betweentangent pixels. In addition, a logical operation on the fit for thesub-image sides may be applied, such as computing the fit for each sideseparately, and taking the median of the fit values. Also, the fit mayneed not use only tangent pixels, instead it may use wider area, such as3 pixels wide. Regarding step 3010, candidate selection mayalternatively be based on other methods, such as taking the candidatewith the maximal occurrence with a minimal fit, or scoring eachcandidate using its occurrence and its fit and selecting the candidatewith the best score.

FIG. 31 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of the background image analyzer 2260 ofFIG. 22. Regarding step 3100, testing if the image is adequate need notbe based on adequacy of all selected candidates. Instead, the criterionfor image adequacy may be that a predetermined percentage, e.g. 95%, ofits portions are adequate. Regarding step 3100, testing if the image isadequate need not use occurrence only, instead it may be based on thecandidate fit in addition to or instead the occurrence.

FIG. 32 is a cartoon illustration of an example of an urban scene inwhich three persons are strolling by, obstructing the scenic background.A moving vehicle and a passing flock of birds also obstruct thebackground. In this cartoon image, an example computation of the extentof occurrence of various portions of the scene is demonstrated. Dottedlines delimit five example portions A, B, C, D and E from among a gridor other plurality of such portions or sub-images, which covers theimage.

The column labeled A, in FIG. 32, depicts a portion of the candidatelist associated with sub-image A and comprising candidates occurringwithin sub-image A. Similarly, the columns labeled B-E depict portionsof the candidate list associated with sub-images B-E respectively.

Portions A-E are characterized as follows:

Portion A: In this portion a car enters the scene. The car brakes inimage 3240 and then remains stationary.

-   -   In the first image, 3210, the sub-image enters the candidate        list, since the candidate list is empty. The occurrence of the        candidate is 1, since it appeared only one time (current time).    -   In the next image, 3220, the sub-image is different than the        candidate (difference is larger than threshold in step 2805).        Therefore, the new candidate is initialized at step 2815.    -   The same is carried out for the next image 3230. Now there are 3        candidates.    -   At the next image, 3240, one more candidate needs to be        initialized. However, since there are already 3 candidates, one        of them is removed to allow the new candidate. Once a sub-image        has been placed in the background image it is typically not        removed, even if it has the lowest occurrence.    -   At image 3250, the sub-image A′ of the scene is same as the top        candidate. Therefore, the occurrence is incremented by 1.    -   At image 3260, the same is carried out as in image 3250. The        occurrence for the top candidate is incremented to 3.

Portion B: In this portion there is a part of a tree, whereas in image3230, there is a flock of birds.

-   -   Image 3210: At the first image, 3210, the sub-image enters the        candidate list, since the candidate list is empty. The        occurrence of the candidate is 1, since it appeared only one        time (current time).    -   Image 3220: Occurrence is incremented to 2 since the sub-image        is similar to the first candidate.    -   Image 3230: Since there is a large variability (step 2610), the        sub-image does not update the candidate list. The occurrence        remains 2.    -   Image 3240: same as 3230.    -   Image 3250 and 3260. Same as 3220, the occurrence being        incremented to 3 and 4, respectively.

Portion C: In this portion there is always a top-left part of the tree.For all images the occurrence is incremented by 1.

Portion D: In this portion there is part of the house, which peoplesometimes pass by and obscure.

-   -   Image 3210: At the first image, 3210, the sub-image enters the        candidate list, since the candidate list is empty. The        occurrence of the candidate is 1, since it appeared only one        time (current time).    -   At the next image, 3220, the sub-image is different than the        candidate (difference is larger than threshold in step 2805).        Therefore, the new candidate is initialized at step 2815.    -   At the next sub-image. 3230, the sub-image is same as the second        candidate, therefore, its occurrence is increased by 1.    -   At the next image, 3240, the sub-image is different than all the        candidates (difference is larger than threshold in step 2805).        Therefore, the new candidate (third one) is initialized at step        2815.    -   At the next sub-image, 3250, the sub-image is same as the third        candidate, therefore, its occurrence is increased by 1. Now        there are 2 candidates with 2 occurrences.    -   At the next image, 3260, the sub-image is different than all the        candidates (difference is larger than threshold in step 2805).        Therefore, the top candidate (with the lowest occurrence) is        removed, and new candidate (top) is initialized at step 2815.

Portion E: In this portion there is another part of the house where onepeople passed in front of. The occurrence is incremented by 1 eachimage, except for image 3240. In this image the sub-image is differentthan the candidate, and a new candidate is initialized.

FIG. 33 is a pictorial and time-line diagram illustrating an example ofthe operation of the noise reduction analysis and control unit 350 ofFIG. 3, according to a preferred embodiment of the present invention. Ina conventional photography process using a long shutter, the noise isreduced but the image is smeared due to camera motion and subjectmotion. A preferred embodiment of the present invention resolves thisproblem.

FIG. 34 is a simplified functional block diagram illustration of thenoise reduction analysis and control unit 350 of FIG. 3, constructed andoperative in accordance with a preferred embodiment of the presentinvention;

Regarding the aligner (unit 3420), the methods described above withreference to FIG. 9 may be employed.

FIGS. 35A and 35B, taken together, form a simplified flowchartillustration of a preferred method of operation for the apparatus ofFIG. 34.

Regarding step 3505, this step may perform alignment which may be basedon the registration methods described in “Image Registration Methods: ASurvey”, Barbara Zitova, Jan Flusser, Imaging and Vision Computing 21(2003), pp. 977-1000 and publications referenced therein. All of theabove publications are hereby incorporated by reference.

Regarding separation step 3510, the methods described above withreference to FIG. 23 are one suitable implementation for this step.

Regarding step 3515, it is appreciated that the “used” or “disregarded”marks need not be assigned using difference between image and previousimage and instead may use other methods such as image flow or histogramdifference, “Used” or “disregarded” marks need not be assigned using theraw data of the images but instead may apply filters, such as smoothingfilter, or transforms, such as Fourier transform, on the images beforecomparing. It is appreciated also that the “Used” or “disregarded” marksneed not be assigned using the difference image but instead it may usethe current night image in the night image memory 3470.

Regarding step 3515, the threshold may not be constant but instead maybe user configured or adaptive based on image content, such asproportional to the average of the difference for all sub-images.Regarding step 3535, testing if the scene is adequate need not be asabove but instead may be based on any other desired criteria.

FIG. 36 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “activechild” mode.

FIG. 37 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “birthdaycake” mode.

FIG. 38 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “don'tblink” mode.

FIG. 39 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “dive” mode.

FIG. 40 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “urban”mode.

FIG. 41 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “night”mode.

FIG. 42 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “race” mode.

FIG. 43 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “child/petrunning” mode.

FIG. 44 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “smile”mode.

FIG. 45 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “surprise”mode.

FIG. 46 is a simplified flowchart illustration of a preferred method ofoperation for the apparatus of FIG. 3 when photographing in “self-photo”mode.

It is appreciated that the present invention is not limited to thespecifics of the methods particularly shown and described hereinabovee.g. in the flowchart illustrations. The present invention relatesgenerally to providing at least one and preferably many functionalitiesfor effecting a corresponding set of one or many selectable photographytasks. It is appreciated that each photography task may be implementedin many ways

It is appreciated that the selectable photography applications providedby a preferred embodiment of the present invention may be either generalor specific. An “object at location” application and a “high motionimage at rest” application are both examples of relative generalapplication. A “birthday cake” application, a “smile” application and a“self photo” application are examples of more specific applications. Itis appreciated that the apparatus shown and described herein may beappropriately modified or expanded in order to obtain apparatusparticularly suited to an essentially number and variety of otherapplications of any level of generality or specificity.

For example, it may be desired to provide a special mode forphotographing handshakes, which is triggered upon detection of contactbetween two moving hands on which the camera is focused, whereindetection and tracking of the hands takes into account knowncharacteristics of hands such as characteristic color or colors, shape,and direction and velocity of motion in the handshake situation. It maybe desired to provide a special mode for photographing graduationceremonies. It may be desired to customize a particular mode for eachtype of sport. So for example, in the tennis-customized mode, thedigital camera system of the present invention might be operative todetect contact between a ball and a racket e.g. by detecting the knownshape and size of a tennis ball and then detecting the deformation ofthe ball object characteristic of its moment of impact with the racket.Imaging would be triggered at that moment of contact. In a pool-jumpapplication, the system of the present invention would preferably takeinto account the information known in this application, namely that achild of generally known dimensions, shape and color is about to jump,from a generally known direction, into a body of water of generallyknown location, shape and color.

Similarly, it may be desired to customize a mode operative to recognizea shower or confetti or a display of exploding fireworks or othereffects, using known image processing based on known attributes of theseeffects, and trigger imaging of those effects at the moment of theiroccurrence. It is appreciated that a sophisticated digital camera systemof the type shown and described herein may provide a user with manydozens of photography options, analogous to conventional electric organsand synthesizers which provide amateur and other musicians with aplethora of selectable musical options.

Similarly, it may be desired to customize various modes for recognizingvarious facial expressions and imaging these at the right time, e.g. asthe target facial expression forms or after it has dissipated. U.S. Pat.No. 5,774,591 to Black et al discusses various publications whichdescribe methods for recognizing facial expressions and applicationstherefor. Many other such methods are known in the field of imageprocessing or can be developed as a direct application of known imageprocessing techniques.

It is appreciated that the methods and apparatus shown and describedherein are particularly suited to applications in which a generallystationary scene, other than one major instance of motion, is to beimaged. For example, the scene might be of a race scene including agroup of generally stationary spectators and one major instance ofmotion namely the running motion of a plurality of athletes. It isappreciated that the apparatus shown and described herein may bemodified to allow the processors to differentiate the major instance ofmotion from other artifactual instances of motion e.g. by knowncharacteristics of the moving object of interest such as but not limitedto color, shape, direction of motion, size and any combination thereof.

It is appreciated that various system-selected and system-computedparameters or settings described herein may be replaced by a user'sselection of the same parameters or settings, typically within theframework of an “advanced user” GUI.

The specific methods and algorithms described herein to implement eachof the analysis and control units of FIG. 3 are only examples of how thevarious selectable photography options shown herein, and other suchoptions, may be implemented. For example, each photography option may beimplemented separately rather than having grouped functionalities whichpertain to a group of several photography options such as the “object atlocation”, “high/low motion”, “facial features”, background building”and “noise reduction” functionalities. Alternatively, differentfunctionalities may be identified. Generally, any system which usesimage processing coupled with a knowledge base characterizing one ormore selectable photography tasks or options, in order to triggerimaging at an appropriate time, as appropriate for the specificphotography task and/or in order to perform photography task-specificimage processing operations to enhance the final photographic product,falls within the scope of the present invention.

It is appreciated that the software components of the present inventionmay, if desired, be implemented in ROM (read-only memory) form. Thesoftware components may, generally, be implemented in hardware ifdesired, using conventional techniques.

It is appreciated that various features of the invention which are, forclarity, described in the contexts of separate embodiments may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention which are, for brevity, described in thecontext of a single embodiment may also be provided separately or in anysuitable subcombination.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove as well as variations and modifications whichwould occur to persons skilled in the art upon reading the specificationand which are not in the prior art.

1. A digital photography method comprising: receiving a definition of amoment at which an anticipated event is to photographed: using a digitalimaging device residing in a digital camera to generate a stream ofdigital images of a location at which said event is anticipated tooccur; and inspecting said stream of digital images, to anticipate saidmoment in said stream, and to generate a trigger timed and constructedto trigger generation of an image of said location at said moment.
 2. Adigital photography system operative in conjunction with a digitalimaging device, the system comprising: a moment definition input devicedefining a moment at which an anticipated event is to photographed; astream of digital images, generated by the digital imaging device, of alocation at which said event is anticipated to occur; and a momentanticipator operative to inspect said stream of digital images, toanticipate said moment in said stream, and to trigger generation of animage of said location at said moment.
 3. A system according to claim 2wherein said moment anticipator resides on an integrated circuit, thesystem also comprising a digital imaging device operative to generatesaid stream and operative in conjunction with said integrated circuit.4. A digital photography method comprising: receiving a definition of amoment at which an anticipated event is to photographed; using a digitalimaging device residing in a digital camera to generate a stream ofdigital images of a location at which said event is anticipated tooccur; and inspecting said stream of digital images, to detect, in saidstream, a digital image which has captured said moment and selectivelystoring said digital image which has captured said moment.
 5. A digitalphotography system operative in conjunction with a digital imagingdevice, the system comprising: a moment definition input device defininga moment at which an anticipated event is to photographed; a stream ofdigital images of a location at which said event is anticipated tooccur; and a moment-catching image selector operative to inspect saidstream of digital images, to detect, in said stream, a digital imagewhich has captured said moment and to selectively store said digitalimage which has captured said moment.
 6. A system according to claim 5wherein said moment-catching image selector resides on an integratedcircuit, the system also comprising a digital imaging device operativeto generate said stream and operative in conjunction with saidintegrated circuit.
 7. A method according to claim 1 wherein saiddefinition of said moment comprises a definition of at least one targetstate of at least one corresponding target object and wherein saidmoment comprises a moment at which at least one target object is in saidat least one target state.
 8. A method according to claim 7 wherein saidtarget state comprises a target location and wherein said momentcomprises a moment at which said target object has reached said targetlocation.
 9. A method according to claim 8 wherein said target objectcomprises a race participant and said target location comprises a finishline.
 10. A method according to claim 8 wherein said target objectcomprises a animal or human subject and said target location comprises auser-selected location.
 11. A method according to claim 8 wherein saidtarget object comprises a diver and said target location comprises alocation along an expected trajectory of a dive.
 12. A method accordingto claim 4 wherein said definition of said moment comprises a definitionof a target state of a target object and wherein said moment comprises amoment at which said target object is in said target state.
 13. A methodaccording to claim 12 wherein said target state comprises a targetlocation and wherein said moment comprises a moment at which said targetobject has reached said target location.
 14. A method according to claim13 wherein said target object comprises a race participant and saidtarget location comprises a finish line.
 15. A method according to claim13 wherein said target object comprises an animal or human subject andsaid target location comprises a user-selected location.
 16. A methodaccording to claim 13 wherein said target object comprises a diver andsaid target location comprises a location along an expected trajectoryof a dive.
 17. A method according to claim 7 wherein said target statecomprises a state at which the target object's level of motion islocally maximal.
 18. A method according to claim 7 wherein said targetstate comprises a state at which the target object's level of motion islocally minimal.
 19. A method according to claim 17 wherein said step ofreceiving a definition of a moment comprises receiving an indicationthat a user wishes to photograph candles being blown out and whereinsaid target object comprises candle flames.
 20. A method according toclaim 18 wherein said target object comprises an active subject.
 21. Amethod according to claim 12 wherein said target state comprises a stateat which the target object's level of motion is locally maximal.
 22. Amethod according to claim 12 wherein said target state comprises a stateat which the target object's level of motion is locally minimal.
 23. Amethod according to claim 21 wherein said step of receiving a definitionof a moment comprises receiving an indication that a user wishes tophotograph candles being blown out and wherein said target objectcomprises candle flames.
 24. A method according to claim 22 wherein saidtarget object comprises a subject with moving limbs.
 25. A methodaccording to claim 7 wherein said target object comprises a face andsaid target state comprises a facial expression.
 26. A method accordingto claim 25 wherein said facial expression comprises a non-blinkingexpression in which the subject is not blinking.
 27. A method accordingto claim 26 wherein said step of inspecting comprises anticipating anon-blinking expression and ensuring generation of a non-blinking imageby generating said trigger upon detection of a blink so as to generatethe non-blinking image before a subsequent blink.
 28. A method accordingto claim 25 wherein said facial expression comprises a smile.
 29. Amethod according to claim 25 wherein said facial expression comprises asurprised expression.
 30. A method according to claim 12 wherein saidtarget object comprises a face and said target state comprises a facialexpression.
 31. A method according to claim 30 wherein said facialexpression comprises a non-blinking expression in which the subject isnot blinking.
 32. A method according to claim 30 wherein said facialexpression comprises a smile.
 33. A method according to claim 30 whereinsaid facial expression comprises a surprised expression.
 34. A digitalphotography method comprising: analyzing a stream of digital images of ascene; and generating an output image of the scene by performing a localimage processing operation selectively on a portion of an image of thescene, said portion comprising an image of less than the entirety of thescene.
 35. A method according to claim 34 wherein said scene includesmoving objects and a background and wherein said local image processingoperation comprises an operation of replacing images of moving objectswith images of the background the objects are obscuring.
 36. A methodaccording to claim 35 wherein said generating step comprises inspectinga plurality of candidate images of a portion of the scene and selectingan individual candidate image from among said plurality of candidateimages which is likely to represent said background.
 37. A methodaccording to claim 36 wherein said selecting step employs at least oneof the following selection criteria: the duration of occurrence of anindividual candidate image; the extent to which the individual candidateimage matches adjacent candidate images.
 38. A method according to claim34 wherein said local image processing operation comprises a noisereduction operation.
 39. A method according to claim 38 wherein saidnoise reduction operation is performed differentially on portions of theimage such that the extent of noise reduction is a decreasing functionof the level of change within said portions.
 40. A method according toclaim 39 wherein said noise reduction operation is performedselectively. only on portions of the image in which there is only aminimal level of change.
 41. Digital camera apparatus comprising: adigital imaging device operative to generate a plurality of preliminarydigital images of a scene defining a plane; a noise reduction processoroperative to generate from said plurality of preliminary digital images.an output image of said scene with a reduced amount of noise, the noisereduction processor comprising an image aligner which uses imageprocessing to generate a plurality of aligned digital images from saidplurality of preliminary digital images by laterally and rotationallyaligning said plurality of preliminary digital images about an axis ofrotation disposed perpendicular to the plane of the scene. 42.Self-photography apparatus comprising: a digital imaging devicegenerating a stream of images of a location; and a self-photographyanalysis and control unit operative to perform image processing on atleast a portion of said stream of images of a location in order toidentify a moment at which an image of said location will comprise asuccessful self-photograph of a photographer's self at that location.43. Apparatus according to claim 42 wherein said self-photographyanalysis and control unit is operative initially, to identify aphotographer's arrival at said location and subsequently, to identifythat the photographer is now motionless at said location.
 44. A digitalphotography system comprising: a digital image stream analyzer operativeto analyze a stream of digital images of a scene; and a local imageprocessing output image generator operative to generate an output imageof the scene by performing a local image processing operationselectively on a portion of an image of the scene, said portioncomprising an image of less than the entirety of the scene.
 45. Adigital photography method comprising: generating a plurality ofpreliminary digital images of a scene defining a plane; generating fromsaid plurality of preliminary digital images, an output image of saidscene with a reduced amount of noise, including use of image processingto generate a plurality of aligned digital images from said plurality ofpreliminary digital images by laterally and rotationally aligning saidplurality of preliminary digital images about an axis of rotationdisposed perpendicular to the plane of the scene.
 46. A method for selfphotography comprising: generating a stream of images of a location; andperforming image processing on at least a portion of said stream ofimages of a location in order to identify a moment at which an image ofsaid location will comprise a successful self-photograph of aphotographer's self at that location.
 47. Multi-mode digital cameraapparatus comprising: digital imaging apparatus operative to generate anoutput image of a location L at a time t: and a time identifieroperative to identify time t as a function of a user-selectedphotography task.
 48. Apparatus according to claim 47 wherein said timeidentifier is operative to anticipate time t and to trigger operation ofsaid digital imaging apparatus at time t.
 49. Apparatus according toclaim 47 wherein said time identifier is operative to select, within astream of digital images generated by the digital imaging apparatus, animage generated at time t.
 50. A multi-mode digital photography methodcomprising: generating an output image of a location L at a time t; andidentifying time t as a function of a user-selected photography task.51. A method according to claim 46 wherein said image processingidentifies a moment at which the photographer has completed at least oneof the following actions: a. has reached location L; b. has becomegenerally motionless; and c. has smiled.
 52. A system according to claim2 wherein said moment definition input device generates a definition ofsaid moment which comprises a definition of at least one target state ofat least one corresponding target object and wherein said momentcomprises a moment at which at least one target object is in said atleast one target state.
 53. A system according to claim 5 wherein saidmoment definition input device generates a definition of said momentwhich comprises a definition of a target state of a target object andwherein said moment comprises a moment at which said target object is insaid target state.
 54. A system according to claim 44 wherein the sceneincludes moving objects and a background and wherein said local imageprocessing operation comprises an operation of replacing images ofmoving objects with images of the background the objects are obscuring.